Game Concepts

Hit points (HP) represent the overall condition of the unit.
Action points (ACP) are what a unit needs to be able to do anything at all. Typically a unit will use 1 ACP to move 1 cell.
Movement points (MP) represent varying costs of movement actions, such as a difficult-to-cross border. The number of movement points is added up then divided by unit's speed to get the total number of acp used up by a move.
Each unit that can do anything has a plan, and a list of tasks to perform.